I left some radish bulbs inI left some radish bulbs in the ground just to see what would happen. They flowered (very pretty little white and pink flowers) and then once the flowers dropped off little pods formed. I opened a pod yesterday and inside was a small round seed. I am going to treat the pods like peas or beans and let them grow until they start to dry out and then pullup the entire plant, seperate the seeds from the pods and let them dry before storing them for the summer. This is all off the top of my head, hope it helps give you some ideas.